Influence of germination on bioactive properties, phytochemicals and mineral contents of Tigernut (Cyperus esculentus L.) tuber and oils

Structure, nutritional composition, and functionality of xylanase/microwave radiation-pretreated tiger nut

In this study, tiger nut was pretreated with xylanase (Xyl), microwave radiation (MW), and a combination of both (MW + Xyl). The structure, nutritional composition, technofunctional, and antioxidant properties of the pretreated and untreated (control) tiger nut flour (TNF) were investigated. The Fourier transform infrared spectroscopic and X-ray diffractrometric spectra of the control and the pretreated samples are similar; however, there was a slight change in some peaks in the pretreated samples, indicating structural re-organization of macromolecules. Scanning electron microscopic images show reductions of surface erosion and formation of clusters in the MW + Xyl-treated TNF compared to the other pretreated samples. Pretreatment increased the protein, Ca, total phenolic content, and swelling capacity of TNF by 3.71-7.31%, 29.41-32.35%, 4.39-9.65%, and 1.59-6.75%, respectively. Meanwhile, 45.52-58.78% and 11.54-15.38% reductions in fat content and water absorption capacity, respectively, were recorded. Pretreatment of TNF with Xyl and MW + Xyl increased its soluble dietary fiber by 26.84% and 64.34%, respectively; however, a 3.31% reduction was recorded following MW treatment. The highest 2, 2-diphenyl-1-picrylhydrazyl scavenging activity (53.20%) was recorded in the MW + Xyl-treated TNF. These findings proved that pretreating TNF with microwave radiation and Xyl could improve its technological and nutritional qualities, enhancing its applicability in food systems.

Tiger nut (Cyperus esculentus L.) oil: A review of bioactive compounds, extraction technologies, potential hazards and applications

Tiger nut is a tuber of a plant native in the Mediterranean coastal countries, which is of great interest in food industry due to its richness in carbohydrates, lipids, starches, minerals, etc. Recent studies have focused on the analysis of the phytochemical composition of tiger nut, including six essential nutrients, polyphenols, and the extraction of proteins, starches, and phenolic compounds from the by-products of tiger nut milk 'horchata'. Few works were focused on the possibility of using tiger nut oil, a nutritious oil comparable to olive oil, as an edible oil. Therefore, this review discussed some extraction technologies of tiger nut oil, and their effects on the properties of oil, such as bioactive compounds, oxidative stability and potential hazards. The information on the emerging applications of tiger nut oil was summarized and an outlook on the utilization of tiger nut oil by-products were also reviewed.

Effects of different tillage systems and mowing time on nutrient accumulation and forage nutritive value of Cyperus esculentus

Revealing the complex relationships between management practices, crop growth, forage nutritive value and soil quality will facilitate the development of more sustainable agricultural and livestock production systems. Cyperus esculentus is known as the king of oil crops and high-quality forage. However, there is little information about the effects of different planting modes {continuous cropping (CC)/rotation cropping (RC)} and initial mowing time on the plant nutrient accumulation and forage nutritive value. Here, in a field experiment, we designed two planting patterns, C. esculentus CC and C. esculentus - wheat RC. The leaves, tubers, roots, and soil samples were collected at three mowing time (on the 78^th, 101^th, and 124^th days after seed sowing). Results revealed that RC significantly increased the total nitrogen (TN) and potassium (TK) content of the tuber (p<0.05), while significantly decreased the TN, total phosphorus (TP), crude protein (CP), and acid detergent fiber (ADF) contents of the leaves. Under the CC pattern, the TN, TP, and TK content of roots increased significantly on the 78^th days after seed sowing, and the TK content of tubers increased significantly. Under the RC pattern, the ether extract (EE) content of tubers increased significantly on the 124^th days after seed sowing, while the CP and TN content of leaves decreased significantly. Correlation analysis showed that soil pH was negatively correlated with TN content in leaves, tubers, and roots. The structural equation model showed that the soil pH directly affected the plant nutrient accumulation and forage nutritive value (β=0.68) via regulating these properties by changing soil available nutrients, anions, cations, and total nutrients. Overall, we propose that RC for C. esculentus-wheat is should not be recommended to maximize tubers and forage yield.

Intake of Natural, Unprocessed Tiger Nuts (Cyperus esculentus L.) Drink Significantly Favors Intestinal Beneficial Bacteria in a Short Period of Time

Horchata is a natural drink obtained from tiger nut tubers (Cyperus esculentus L.). It has a pleasant milky aspect and nutty flavor; some health benefits have been traditionally attributed to it. This study evaluated the effects of an unprocessed horchata drink on the gut microbiota of healthy adult volunteers (n = 31) who consumed 300 mL of natural, unprocessed horchata with no added sugar daily for 3 days. Although there were no apparent microbial profile changes induced by horchata consumption in the studied population, differences could be determined when volunteers were segmented by microbial clusters. Three distinctive enterogroups were identified previous to consuming horchata, respectively characterized by the relative abundances of Blautia and Lachnospira (B1), Bacteroides (B2) and Ruminococcus and Bifidobacterium (B3). After consuming horchata, samples of all volunteers were grouped into two clusters, one enriched in Akkermansia, Christenellaceae and Clostridiales (A1) and the other with a remarkable presence of Faecalibacterium, Bifidobacterium and Lachnospira (A2). Interestingly, the impact of horchata was dependent on the previous microbiome of each individual, and its effect yielded microbial profiles associated with butyrate production, which are typical of a Mediterranean or vegetable/fiber-rich diet and could be related to the presence of high amylose starch and polyphenols.